The Brexit Party, The Liberal Democrats, the Green Party and Change UK have all held their final rallies of the European election campaign.
Nigel Farage urged Tory Eurosceptics angry over Brexit to back his party and vowed a “peaceful political revolution” to end the two-party system.
Vince Cable said a strong showing for the Lib Dems would advance the “wider cause of stopping Brexit”.
Campaigning is in its last 48 hours ahead of Thursday’s polls.
With the campaign drawing to a close, pro and anti-Brexit parties are focused on rallying their supporters and getting out their vote.
The Brexit Party
The party said 3,000 people attended its closing rally in Olympia in West London.
The crowd was addressed by Ann Widdecombe, the former Conservative minister who is standing as a candidate in the South West of England, and the party’s chairman Richard Tice.
Closing the rally, Mr Farage said the UK’s political class could not be trusted and congratulated his supporters on making “the establishment absolutely terrified”.
The Liberal Democrats
The Lib Dems held their largest rally of the campaign on the other side of the capital, close to Waterloo station.
Activists heard from, among others, former leader Tim Farron and the party’s education spokeswoman Layla Moran.
Vince Cable urged supporters to campaign “until the last vote is cast”, something he said his party was famous for.
Change UK brought its debut political campaign to an end with a rally in Manchester.
Former Labour MPs Chuka Umunna and Chris Leslie addressed supporters, as did several of the party’s candidates in the North West region.
Former Conservative MP Anna Soubry urged supporters to “get out there and speak to all of those people who believe our great country has made a terrible mistake” over Brexit.
The Green Party
Former Green Party leader Caroline Lucas addressed a rally in Oxford, which also heard from the city’s former Lord Mayor Elise Benjamin, who is standing as a candidate.
Ms Lucas said her party was campaigning hard for a referendum on the terms of Brexit and dismissed the PM’s offer to give MPs a vote if they back the Withdrawal Agreement bill.
She likened Mrs May’s revised Brexit offer to MPs to “putting lipstick on a pig”.
The other parties
The Conservatives and Labour, which both back a negotiated Brexit, are not expected to hold any official events in the last 48 hours of the campaign.
But candidates from all the leading parties, also including UKIP, will be campaigning up to the wire.
On Thursday, voters will go to the polls in nine electoral regions across England, as well as in Wales, Scotland and Northern Ireland, to elect 73 MEPs.
The results will be announced from 22:00 BST on 26 May.
A full list of candidates for all the constituencies can be found here.